The Exe Valley Railway was a branch line that ran from a junction with the Great Western main line at Stoke Canon to Dulverton where it met the now closed Devon and Somerset railway that connected Taunton to Barnstaple. The line closed to passengers in 1963 and this quiet part of mid Devon lost its link to the rest of the railway network.
Much of the route is in private hands and plans to create a cycle route along the former railway alignment have not progressed in the 20 or so years I have been cycling around this area. Despite this, the lack of modern development means that many embankments, bridges and cuttings are still visible.
To find the cache proceed to the headline coordinates and you will be on the site of a former level crossing. You will see a metal object (I would appreciate your thoughts on what this is in your logs) that has a letter followed by three numbers. Call the numbers X, Y and Z and you will find the cache at:
N 50 48. Z (X+1) Y
W 003 30. (X+Y) Y Z
You will be looking for a small clip lock box covered in camouflage tape. Expect some mud in the vicinity of GZ if the weather has been wet in the previous few days.